BT has also cut off access to other addresses, known as proxy sites, made available by The Pirate Bay.

But a representative of the UK Pirate Party - a political group that opposes the bans - told BBC News more proxy sites had been made available "within minutes".

About 10% of traffic to its proxy sites now seemed to be coming from BT customers, 30% from VirginMedia customers, 15% via Sky, 6% via TalkTalk and 3% via O2, he said.

BT declined to comment on reports the block had been circumvented.

The Pirate Party spokesman said public interest in the service following the ban had also boosted traffic to the party's website.

Democratic process

"This increased traffic isn't just about The Pirate Bay; it seems that the proxy has sparked an interest in the Pirate Party itself, and we are seeing a significant uptick in membership and people navigating the rest of the site," he said.

"The volume of emails and phone calls into the party has also increased markedly."

The spokesman added: "Blocks on Pirate Bay have effectively short-circuited the democratic process.

"Our internet policy is not being run by our elected representatives, it is being dictated by the music industry."